1. Field of Invention
This invention relates to automatically identifying a marking process used to form an image on a substrate.
2. Description of Related Art
In order to accurately calibrate a scanner, such as, for example, a color scanner, that scans an image carried on a substrate, different calibration transformations are required depending on the marking process, such as, for example, photography, inkjet printing, xerography, lithography and the like, and materials, such as, for example, toner, pigment, ink, etc., that are used to form the image on the substrate. For example, a calibration transformation that is used to calibrate the scanner for a photographic image is different from a calibration transformation that is used to calibrate the scanner for an ink jet-printed image, which is in turn different from a calibration transformation that is used to calibrate the scanner for a xerographically-formed image or for a lithographically-formed image.
Typically, a user wishing to scan an image determines the marking process used to form the image from prior knowledge of the marking process, manually identifies the marking process such as, for example, photographic, ink jet, xerographic or lithographic, and uses the marking process information to set the scanner so that an appropriate calibration can be used. The manual identification is commonly done using different descriptions, such as Halftone vs. Photo vs. Xerographic Copy on the user interface from which different machine settings are inferred.
Approaches to automatically identifying the marking process are disclosed in U.S. Pat. Nos. 6,353,675 and 6,031,618, each of which is incorporated herein by reference in its entirety. The approach to automatically identifying the marking process disclosed in the 618 patent uses additional spectral information from the scanned material obtained through additional spectral channels. The approach used to automatically identify the marking process disclosed in the 675 patent involves an image spatial analyzer that analyzes image data corresponding to the image to determine at least one spatial characteristic based on a power spectrum of the image data and a marking process detection system that detects the marking process based on the at least one spatial characteristic.